Referring to FIGS. 1A and 1B, which are described in detail below, a known central display device 30 is illustrated with five vertical reels 34 and a payline 56. The gaming industry standard is to provide three to five vertical reels and display three symbols per reel, as illustrated. The paylines 56, which are sets of adjacent or juxtaposed symbols that the game analyzes to determine if the game has randomly generated a winning symbol or symbol combination, typically do not include more than one symbol from each reel. Including more than one symbol from the same reel on the same payline disrupts the mathematics of the game because one random number generating device, the reel, can supply more than one winning symbol or winning symbol combination component. The implementor would thus have to consider the relative spacing of the symbols on the reel, not just the number of symbols on the reel, in determining the odds of generating any particular symbol or symbol combination.
Many known gaming devices display multiple symbols of a single reel and accordingly display multiple symbols when the reels spin. These known games typically include at least one reel having a different symbol distribution than the other reels. Different symbol distributions provide the game designer or implementor flexibility in designing winning combinations and varying payouts. Many known gaming devices include multiple paylines, such as payline 56. When the multiple paylines include more than one or all the reels of the game, the symbol distribution of each reel determines some of the game characteristics that limit the game implementor.
In an effort to provide a gaming device capable of more flexible payline layouts, manufactures have developed gaming devices displaying a plurality of columns of symbols as illustrated in FIGS. 1A and 1B, but wherein each symbol is included on a separate reel. That is, referring to the furthest right reel 34 of FIGS. 1A and 1B, the bell, the seven and the cherries each represent, are part of and are included on a separate reel. Each “unisymbol display reel” thus displays one symbol to the player on the display. In FIGS. 1A and 1B, there would be fifteen different reels if the figures included unisymbol display reels. Unisymbol display reels typically exist as simulated symbols on video monitors. IGT, the assignee of this invention, manufactures and distributes a nine reel game called ‘Super 8 Race’, which includes unisymbol display reels in a 3 by 3 matrix.
Referring to FIG. 3, an exploded representation of a prior art unisymbol display embodiment is illustrated having nine separate displayed symbols “A” through “I” of a central display device 30 and nine respective exploded reels 100 through 116. The reels 100 through 116 each include a single symbol (or blank) displayed on the central display device 30. A rotational arrow is also illustrated for each reel 100 through 116 indicating that any symbol on the central display device 30 can change individually.
FIG. 3 also illustrates paylines one through eight connecting the symbols. The unisymbol display reels 100 through 116 enable vertical paylines, as illustrated by paylines four, five and six because the relative spacing problems associated with vertical paylines on multisymbol display reels are inapplicable. Symbol “A” is included on a reel that is different from the reel of symbol “D”, etc.
Unisymbol display reels also enable the implementor to design highly unlikely winning combinations with very large payouts, which players' desire, and which typically cannot exist on normal multisymbol display reels. For a player playing all eight paylines, for example, the implementor can create a large payout for the random generation of nine of any particular symbol, “e.g.” nine “A's”, one on each reel. A three by three multisymbol display reel would have to place three of the same symbols next to each other on the three separate reel strips to create the possibility of displaying nine of the same symbol. As stated above, this disrupts the mathematics of the game because the odds are dependent on the relative spacing of the symbols on the reel.
Unisymbol display reels have a drawback in comparison with multisymbol display reels. Referring again to prior art FIG. 3 and assuming that a winning combination of any three adjacent “A” symbols on a payline yields an award, the mathematics of the game dictate that each reel contains the same proportion of “A” symbols. If, for instance, the reels 100 through 114 include one “A” symbol and reel 116 includes two “A” symbols, and assuming each reel strip has ten symbols, the odds of obtaining an “A”, “A”, “A” combination would vary depending upon which payline the player played. That is, the odds of obtaining an “A”, “A”, “A” combination on paylines one, two, four, five and eight are (1/10)×(1/10)×(1/10) or 1000:1. However, the odds of obtaining an “A”, “A”, “A” combination on paylines three, six and seven are (1/10)×(1/10)×(2/10) or 500:1. The differing odds force the game to maintain separate payouts for the same winning combination and cause player confusion.
Another drawback arises when in a winning symbol combination such as “A”, “A”, “A”, a necessary symbol, i.e., “A” is not included on one of the reels, e.g., reel 116. In this situation, the winning paylines one, two, four, five and eight enable the player to win the award associated with the “A”, “A”, “A” combination, whereas paylines three, six and seven do not. With both drawbacks, differing reel strips create payline inequities that force the gaming device implementors to place the same proportion of the same symbols on each of the reels strips. The current apparatus configuration and method for evaluating winning combinations thus severely restricts the flexibility of the design of a game having unisymbol display reels.